Control mechanism



May 9, 1944.

P. F. sczoFlELD ETAL CONTROL MECHANISM Filed Feb. 18, 1945 4 Sheets-Sheet 1 IN VHV TORS May 9, 1944. P. F. Scor-'IELD TAL 2,348,656

` CONTROL MEGHAMSM Filed Feb. 18, 1943 4 sheets-sheet 2 ira/Mfr May 9, 1944.

P. F. SCOFIELD E TAL CONTROL MEGHANSM Filed Feb. 18, 1943 4 Sheets-Sheet I5 .May 9, 1944. P. lF. scoFlELD ETAL '2,348,556

CONTROL MEC'HANISM Filed Feb. is, 194s 4 sheets-sheet 4 Patented May 9, 1944 CONTROL MECHANISM Philip F. Scofield and Davidy J. Conant, Cleveland Heights, Ohio, assignors to Jack & Heintz, Inc., Bedford, Ohio, a corporation of Ohio Application February 18, 1943, Serial No. 476,341

7 Claims.

This invention relates to an electric control mechanism adapted to be operated by both manual and automatic instrumentalities.

The object of the invention is to provide an improved switching and control mechanism in an energizer for aircraft inertia starters which may be operated by manual means, governor means and overload responsive means.

A preferred embodiment of the invention is illustrated in the accompanying drawings in which:

Figure l is an elevational View of an energlzer having a control mechanism embodying the principles of the invention;

Figure 2 is an enlarged partial sectional view of the energizer illustrating the switching device and governor;

Figure 3 is a view showing the switch mechanism in off position, corresponding to Figure l;

Figure 4 shows the switch mechanism in on position;

' Figure 5 shows the switch mechanism after being tripped to off postiion by the governor, the manually operated parts being still held in on position; andV Figure 6 is a top view of the switching device.

The energizer is indicated generally by the numeral i in Figure l, the device being powered by a motor 2 and provided with a handle 3 for manipulating the device. Adjacent the handle is a switching device 4 arranged for manual operation by a grip member 5 in the handle and also by a governor 6 on the end of the motor shaft. Manual setting and tripping of the switching device is effected through a lever 1 connected to the grip member 5 through a link 2, a spring 9 serving to bias the grip member toward the position shown. Governor actuation of the switching device is effected by a plunger l0 arranged to bear against a tripping lever il.

Reference will now be made to Figure 2 for a description of the governor 6. The numeral i2 designates the shaft of motor 2, the same being carried at the commutator end in a .bearing i3 contained in a bearing housing I4. The shaft I2 terminates in a U-shaped member l5 carrying governor weights I8 pivoted on pins lv'l. Weights I6 are provided with -bell crank arms i8 adapted to engage a head I9 on a pin 20 seated within the plunger l0. A spring 2l urges the plunger and pin inwardly di housing i4, and they are thereby constrained to remain in this position until the speed of shaft i2 is sufficient 'to cause the governor weights I8 to cam these parts outwardly and into engagement with tripf ping lever Il.

The operating parts of the switching device 4 are carried by a frame 30 contained in an insur lating housing 3|. Also contained within the housing 3| on opposite sides thereof are two pairs of stationary contacts 32 and 33 carried by insulating sheets 34 and 35. A rotary contact bridging member 36 is disposed between the stationary contacts, having arms 31 and 38 operated by snap action to occupy either the full line or broken line positions shown in Figure 2. It is understood that the organization shown in Figure 2 is duplicated on the other side of housing 3l to open both sides of the line.

The mechanism for operating the two bridging members 36 is shown in Figures 3, 4 and 5. The lever 'l is pivoted at 39 to the frame 30 and isprovided with pivots 40 and 4I for carrying, respectively, a spring abutment lever 42, and an arm 43. The frame 30 is providedvin its opposite sides with V-shaped openings 44 having bearing portions 45 to fulcrum a yoke 46 therein, the margins of the openings serving as stops to limit the swing .of the yoke. The yoke 46 is of inverted U-shape, containing a tension spring 41 between the legs of the U, one end of said spring being hung in a notch 48 on spring abutment lever 42 and the other being hung in a notch 49 in the yoke. The lower extremity of each leg of yoke 4 carries one of th'e contact lbridging members 36 keyed thereto concentric with the fulcrum 45 so that the arms 31 and 33 move with the yoke.

Figure 3 shows the parts in normal set position with grip 5 extended and member 36 in ofi position. When the grip 5 is squeezed into handle 3 the link 8 rotates lever 'l clockwise on its pivot 39. The upper end of arm 43 engages a detent 5i in a trip arm 5i) causing the arm 43 to move with lever l, the lower end of arm 43 having a hook 52 engaging a projection 53 on the spring abutment lever 42, causing the three members 1, 43 and 42 to move together from the position of Figure 3 tothe position of Figure 4. When the notch 48 passes over center with respect to fulcrum 45 the spring lll snaps the yoke 46 to the left to close the motor circuit.

The parts remain in the closed circuit positions of Figure 4 as long as grip 5 is depressed. Upon release of grip 5 the spring 9 returns the parts to the positions of Figure 3, opening the circuit.

As previously stated, the switching mechanism also provides for opening the 'motor circuit by the governor 6. When the motor exceeds a predetermined safe speed the governor weights I6 vextend the plunger l so as to depress the outer end of tripping lever Il as shown in Figure 5. Tripping lever Il raises the trip arm 50 on its pivot 55 against the force of spring 56, this motion raising the detent I clear of the abutting end of arm 43. When arm 43 is thus freed lt swings clockwise on its pivot 4I so that hook 52 moves down to release projection 53. This release frees spring abutment lever 42 to swing to the right, or counterclockwise, on its pivot 40 under the tension of spring 41 until a toe 51 is stopped by a wall 58 in the frame 30. This last described movement of spring abutment lever 42 from the position of Figure 4 to the position of Figure 5 carries the notch 48 back over center with respect to fulcrum 45, snapping the yoke 4B and contact arms 31 and 38 to open circuit position with all parts in the 'positions shown in Figure 5. Release of grip 5 allows the spring 9 to return the lever 1 to the right with the switch arms remaining in oiI position.

When lever 1 is moved to the right by spring 9 after the mechanism has been tripped by the governor' an elbow 59 on spring abutment lever 42 engages the arm 43 above its pivot 4i swinging the top of arm 43 to the left and resetting it behind the detent 5I, provided that the plunger I0 is sufficiently retracted by that time. The

switch cannot be again turned on however untilv arm 43 is set behind the detent 5i. In this manner, all parts of the mechanism are reset to the positions shown in Figure 3 in readiness for furtherI operation of the motor.

The switching mechanism also includes overload current responsive tripping means. In series with one line to the motor is a. short loop of resistance wire 60 adapted to develop heat on overload suillcient to warp a bimetallic bar 6l. The bar 6l is attached in cantilever fashion to an overhanging portion 62 on the frame 30, adjustment being obtained by means of screwr 63. The central portion of bar 6I lies across the area heated by the resistance element 60, and the extremity of bar 6I extends under one side of a T-head 64 on trip arm 5B. Thefarrangement is such that when the motor circuit draws an excessive current for a time suilicient to heat the thermostat before the heat is dissipated the latter will lift the trip arm 50 to break the circuit in the saine manner described in connection with the operation of the governor.

Figure 6 shows the manner in which the T- head 64 on trip arm 50 is arranged for actuation by either the thermostat 6| or the governor operated tripping lever l l. The hermostatic strip extends from the right under one side of the head 64, and the lever II extends from the left under the other side of head 64. The lever vIl is pivoted at 65 cna bridge member G6 secured by screws 61 directly to the frame 30. The bridge member 66 rests on the surface of a stii insulating sheet 68 covering the operating mechanism contained within the insulating housing 3i.

lI'he insulating housing 3| is preferably of box-like form, enclosing and containing the switching mechanism in the manner described. The top of the box is closed by a cover member 69 having an opening 1li over the tripping lever Il for receiving the end of plunger I0, as shown in Figure 2, the arrangement being such that by disconnecting the link 8 the box 3l including the complete switching mechanism may be conveniently removed as a self-contained unit without disturbing the governor or other operating parts.

Various changes in the arrangement and construction will occur to persons skilled in the art Yand all such modincations are included in the invention. The invention is to be limited only by the scope of the prior art and the appended claims.

We claim:

1. In an energizer for an aircraft inertia start er, a motor, a switch mechanism for controllin! said motor, a movable hand grip for manually operating said switch, a governor driven by said motor for operating said switch, and means operable upon release of said hand grip for setting said mechanism for another cycle of operation.

2. In an energizer for an aircraft inertia starter, a motor, a switch mechanism for controllingy said mechanism, an independent release means, l

means arranged to be set by said hand grip and releasable by said release means to open said switch. and a governor driven by said motor for actuating said independent release means.

4. In an energizer for an aircraft inertia starter, a motor, a switch for controlling said motor, snap acting mechanism for closing and opening said switch, a movable hand grip for operating said mechanism, an independent release means. means arranged to be set by said hand grip and releasable by said release means to open said switch, a governor driven by said motor for actuating said independent release means, and a current responsive overload release device for actuating said independent release means.

5. In an energizer for an aircraft inertia starter, a motor, an enclosed bearing housing receiving one end of the shaft of said motor, a governor contained within said bearing housing and having a speed responsive plunger extending axially therefrom, a unitary switching mechanism contained within an insulating housing adjacent the end of said bearing housing, a movable hand grip member for operating said switching mechanism and for setting said switching mechanism for operation by said governor, and an opening in said insulating switch housing receiving the end of said plunger therein for operating said switching mechanism.

6. In an energizer for an aircraft inertia starter, a unitary switching mechanism, a lever for manually opening and closing said switch and for setting said mechanism for release by an independent instrumentality, a trip arm for effecting said release, a tripping lever for operating said trip arm, an insulating housing containing said switching mechanism as a unit including said trip arm and tripping lever, and an opening in said housing adapted to receive a plunger in operative relation with said tripping lever.

7. In an energizer for an aircraft inertia starter. a unitary switching mechanism, a lever` for manually opening and closing said switch and for setting said mechanism for release by a plurality oi' independent instrumentalities, a trip arm for effecting said release, an upstanding T-head on said trip arm, an overhead current responsive thermostatic member having a movable portion underlying one side of said T-head, a bridge support on said mechanism; a tripping lever pivotally mounted on said support and having one end underlying the other side of said T-head, an insulating housing containing all of said above recited structure therewithin, and an opening in said housing adapted to receive a plunger in operative relation with said tripping lever. whereby said release may be eiected by said thermostatic 5 member or by said plunger.

PHILIP F. SCOFIELD. DAVID J. CONANT.

CRTIFICATE oF co-RBEQTION. 1 Patent Nn. 2,5LLS,656. y may 9, 191m.

PHILIP F. scoFIEL'D, 'ETALJ It 1e hereby certifiedthat error ppears in the printed specificgtion of the above numbered patent requiring correction as follows: Page 5, first column, line' 2,- claim 7, for the word overhead read -over1oad; .and

that the said Letters Patent should be .reed with-this correction therein that the same may conform to the record of the case in the Patent Office.

signed and sealed this aanacmy of August, A. D. 19141.

Leslie Frazer 1(Seal) l Acting Commissioner of Pateni'ns.A

'GRTIFICATE' oF coRBEoTIoN. Patent No. 2,5MB,656. May 9, 19ML- PHILIP F. scoFIEL'D, 'ET AL.'

It 1e hereby certifiedthat error elppears in the printed specification of the above mnnbered patent requiring correction as follows: Page 5, first column, lin'e 2,- claim T, for the word overhead read over1oad; vand Athat the said. Letters Patent should be 4reed with-this correction therein that the same may confom to the record of thei case in the Patent Office.

Signed and sealed this 22:15:16.133v of August, A. D. 191414..

Leslie Frazer "(Seal) y I f Acting Commissioner of Patents., 

